Recent neuropathological and imaging studies support the concept of “brain-first vs. body-first” Parkinson’s disease (PD), which is based on the α-synuclein origin site and connectome model. The body-first phenotype is characterized by early involvement of the peripheral autonomic nervous system, particularly the cardiac sympathetic nerves and enteric nerves. 123I-meta-iodobenzylguanidine (123I-MIBG) myocardial scintigraphy is a well-established method for evaluating cardiac sympathetic innervation. This review explores the potential of 123I-MIBG scintigraphy as a biomarker to differentiate the body-first phenotype from the brain-first phenotype. Reduced 123I-MIBG uptake has been observed in idiopathic rapid eye movement (REM) sleep behavior disorder, pure autonomic failure, and incidental Lewy body disease—conditions strongly associated with prodromal or early-stage PD. Postmortem and biopsy evidence indicates α-synuclein accumulation in cardiac nerves and other peripheral sites, which is consistent with bottom-up progression. α-Synuclein seed amplification assays further corroborate the association between the peripheral α-synuclein burden and reduced 123I-MIBG uptake. While 123I-MIBG myocardial scintigraphy is a promising tool, its limitations include cost, limited availability, and potential confounding from underlying cardiac conditions. Nonetheless, early detection of cardiac sympathetic denervation via 123I-MIBG imaging may enhance diagnosis, support subtype classification, and improve the understanding of PD pathogenesis.

Objective: This study aims to investigate the clinical relevance of occipital hypoperfusion in patients with Parkinson’s disease (PD) with respect to clinical phenotype and the risk of dementia conversion. Methods: We enrolled 349 patients with newly diagnosed PD and 48 healthy controls who underwent dual-phase 18F-N-(3-fluoropropyl)-2β-carboxymethoxy-3β-(4-iodophenyl) nortropane (18F-FP-CIT) positron emission tomography (PET). Patients with PD were classified into three groups based on posterior cortical perfusion patterns on early-phase 18F-FP-CIT PET images: PD with preserved posterior cortical perfusion (n=186), PD with parieto-temporal hypoperfusion (n=84), and PD with parieto-temporo-occipital hypoperfusion (n=79). Baseline clinical features and dementia conversion risk were compared across PD groups. Results: Patients with preserved posterior cortical perfusion were younger than those in the other PD groups. Compared with the other groups, the parieto-temporo-occipital hypoperfusion group tended to have lower Cross-Cultural Smell Identification Test scores, a higher prevalence of rapid eye movement sleep behavior disorder, higher Unified PD Rating Scale motor scores, and more severe reductions in striatal dopamine transporter availability. The risk of dementia conversion was lower in patients with preserved posterior cortical perfusion than in those with posterior cortical hypoperfusion. However, the risk of dementia conversion did not differ between the parieto-temporal and parieto-temporo-occipital hypoperfusion groups. Conclusion Additional occipital hypoperfusion was not associated with an imminent risk of dementia conversion in patients with PD with posterior cortical hypoperfusion. Nonetheless, occipital involvement may serve as an indicator of the diffuse malignant subtype of PD.

Objective: Sleep disturbances are common and debilitating nonmotor symptoms (NMS) in Parkinson’s disease (PD) patients and profoundly affect quality of life. Despite emerging evidence suggesting that monoamine oxidase B (MAO-B) and catechol-O-methyltransferase (COMT) inhibitors may alleviate NMS, their specific effects on sleep remain unclear. The aim of this network meta-analysis (NMA) was to compare the efficacy of these inhibitors related to sleep problems in PD patients. Methods: Following a systematic search of PubMed, Cochrane, and Embase, studies comparing MAO-B or COMT inhibitors and assessing sleep outcomes in PD patients were identified. An NMA was conducted using data from the seven studies that met our inclusion criteria. The outcomes included subjective sleep quality, daytime sleepiness, and objective polysomnography (PSG) parameters. Results: No statistically significant differences were found between the effects of the MAO-B and COMT inhibitors on improving subjective sleep quality or daytime sleepiness. However, analyses of objective PSG data revealed that, compared with rasagiline and placebo, safinamide significantly increased rapid eye movement sleep duration (mean difference, 5.70 min [95% CI, 2.26 to 9.14]) and decreased wake time after sleep onset (mean difference, -10.20 min [-19.38 to -1.02]). Conclusion These findings suggest that safinamide may offer additional value for managing sleep disruptions beyond its known motor benefits in patients with PD. Given the limited number and small scale of available trials, the overall evidence should be interpreted cautiously. Nonetheless, this analysis highlights the need for future high-quality trials focused on sleep outcomes to guide the personalized use of MAO-B and COMT inhibitors for sleep disturbances in PD patients.

Objective: The NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome has been proposed to be a downstream mediator of neuroinflammation in individuals with Parkinson’s disease (PD). However, its involvement across disease stages and related synucleinopathies, such as multiple system atrophy (MSA), remains unclear. We aimed to analyze the peripheral mRNA expression of NLRP3-related genes and cytokines across individuals with isolated REM sleep behavior disorder (iRBD), early-stage PD, late-stage PD, and MSA. Methods: Peripheral blood mononuclear cells (PBMCs) were collected from 151 participants: 35 healthy controls (HCs), 31 patients with iRBD, 41 patients with early-stage PD, 21 patients with late-stage PD, and 23 patients with MSA. mRNA expression was measured using quantitative real-time polymerase chain reaction. Statistical comparisons were performed using analysis of variance (ANOVA) or Welch’s ANOVA, and associations with clinical variables were analyzed through stepwise multiple linear regression. Results: NLRP3 expression was significantly lower in patients with iRBD (p=0.0263) and patients with early-stage PD (p= 0.0101) than in HCs. NIMA-related kinase 7 (NEK7) expression progressively decreased across the disease spectrum (HCs vs. patients with early-stage PD, p=0.0008; vs. patients with late-stage PD, p<0.0001). In contrast, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) and caspase-1 were elevated in patients with PD, especially those in the late stages. Levels of patients with MSA resembled those of HCs but differed from those of patients with PD. Interleukin (IL)-1β and IL-18 levels were not significantly different. In patients with early-stage PD, NLRP3 expression was negatively correlated with disease duration, the Movement Disorder Society-Unified Parkinson’s Disease Rating Scale Part II score, and the cognitive score. Conclusion Our findings challenge the prevailing hypothesis that NLRP3 inflammasome activation directly contributes to PD pathogenesis. Instead, the observed increase in ASC and caspase-1 expression suggests the potential involvement of alternative inflammasome pathways during disease progression.

Nocturnal hypokinesia (NH) is common in patients with moderate-stage Parkinson’s disease (PD). This open-label, single-arm pilot study aimed to assess the effect of bedtime opicapone administration on NH and to evaluate the clinical utility of the Nocturnal Hypokinesia Questionnaire (NHQ). The primary endpoint was the change in the NHQ score from baseline to week 6. Fifteen patients were included. The mean change in the NHQ score after the 6-week treatment was -0.9 points (95% confidence interval [CI]: -2.4, 0.5; p=0.187), which was not statistically significant. However, NHQ domain 2 (getting out of bed) significantly improved, with a mean change of -0.3 points (95% CI: -0.6, -0.1; p=0.025). The administration of opicapone in patients with PD and NH did not result in a significant improvement in NH, although it was associated with an improvement in the single domain of getting out of bed. Further studies are needed to establish the efficacy of opicapone for treating NH.

Objective: Globus pallidus internus deep brain stimulation (GPi-DBS) is an established treatment for dystonia, but its specific efficacy for tardive dystonia (TD) remains insufficiently documented. To evaluate the long-term clinical outcomes of GPi-DBS and to identify optimal stimulation sites in patients with medically refractory TD. Methods: We retrospectively analyzed data from 26 patients with TD who underwent bilateral GPi-DBS. Clinical outcomes were assessed using the Burke–Fahn–Marsden Dystonia Rating Scale (BFMDRS). Optimal stimulation sites were identified using voxelwise sweet spot analysis. Results: At an average follow-up time of 42 months (range 12–4 months), the mean BFMDRS score improvement was 81.5%. The optimal stimulation sites were located in the posteroventral region of the GPi. Two patients experienced sustained symptom remission after DBS cessation. Complications included device-related infection (n=2), dysarthria (n=4), and gait imbalance (n= 1); no severe permanent complications occurred. Conclusion GPi-DBS is effective and safe for patients with medically refractory TD, providing significant long-term symptom relief. The optimal stimulation sites were located in the posteroventral GPi, which is consistent with those reported for patients with other dystonia types.